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Cougar prey use in a wildland-urban environment in western Washington.

ABSTRACT--The Cougar (Puma concolor) is an apex predator whose occurrence and space-use patterns are closely tied to the abundance and vulnerability of ungulate prey. Deer (Odocoileus spp.) and Elk (Cervus elaphus) readily use residential portions of the landscape, but little is known of Cougar prey use within these environments. We used Global Positioning System and VHF relocation data from 20 Cougars to examine prey use in a wildland-urban landscape in western Washington. We tested for differences ([alpha] = 0.10) between wildland and residential prey compositions using the Chi-square test of homogeneity and used an ANOVA fixed-effects model to determine the potential influence of residential development on the duration of Cougar presence on kills. We located 304 kills throughout the study area with Black-tailed Deer (Odocoileus hemionus columbianus, 55.3%), Beaver (Castor canadensis, 22.0%), and Elk (8.8%) constituting the bulk of Cougar diet. Wildland and residential prey compositions were significantly different, with Cougars killing a higher proportion of Deer, Beavers, and Mountain Beavers (Aplodontia rufa) in wildland areas and more Coyotes (Canis latrans), Raccoons (Procyon lotor), Opossums (Didelphis virginiana), and domestic species close to residential development. Kill location did not have a significant effect on the duration of stay regardless of species killed, nor was the effect of location significant when comparing kills of the same species. Cougar diet in wildland-urban forests of western Washington is diverse, but Cougars do not appear to shift their space-use patterns to take advantage of non-ungulate prey close to residential development. However, long-term management of Cougars in wildland-urban environments may require an examination of ungulate presence in residential environments to ensure that these populations do not encourage Cougar presence in habitats close to people.

Key words: Cougar, predation, Puma concolor, residential development, western Washington, wildland-urban interface


The expansion of human populations and alteration of wildland habitats has created many challenges for wildlife management and conservation. Although many mammals experience detrimental consequences associated with habitat loss and fragmentation (Jordan 2000; Brady and others 2009; Mortelliti and others 2010), effects on large carnivores can be particularly acute because of their low population densities coupled with extensive area and prey biomass requirements (Fuller and Sievert 2001; Inskip and Zimmerman 2009; Rutledge and others 2010). Considerable efforts have been undertaken to understand and address the impacts of human expansion on the long-term viability of many species (for example, Jackson and Nowell 1996; Linnell and others 2001; Novaro and Walker 2005; Muntifering and others 2006), but many aspects of carnivore ecology in wildland-urban environments remain unknown. Predation patterns are a fundamental component of large carnivore ecology and behavior, and large carnivore space use is closely tied to the distribution of prey (Thaker and others 2011). Consequently, management and conservation of large carnivores in a wildland-urban environment requires baseline information on prey use and how it may differ in wildland and residential portions of the landscape.

The Cougar (Puma concolor) is an apex predator capable of exerting top-down influences on ecosystems and prey (Bowyer and others 2005; Ripple and Beschta 2006). Cougars are distributed widely throughout the western hemisphere with their occurrence closely tied to the presence of large, ungulate prey (Sunquist and Sunquist 2002; Murphy and Ruth 2009). Historically, the Cougar was perceived as a wilderness species requiring large tracts of wildland habitat with limited anthropogenic disturbance and abundant prey (Gill 2009). Wildlands are critical for the long-term viability of populations (Dickson and Beier 2002; Cox and others 2006; Beier 2009), but recent evidence demonstrates Cougars can, and do, use residential areas (Beier and others 2010; Kertson 2010). Wildland-urban environments comprise undeveloped (0 residences/ha) and residential (>0 residence/ha) areas that create a mosaic of suitable and unsuitable habitat for Cougars (Kertson 2010). Prey abundance and vulnerability are significant factors determining Cougar space use patterns (Williams and others 1995; Dickson and Beier 2002; Robinson 2007; Kertson and others, in press) and ungulates readily use residential areas (Happe 1982; McCullough and others 1997; Bender and others 2004a). Understanding how Cougars use ungulate and non-ungulate prey in wildland and residential portions of the landscapes may provide insights on Cougar presence in residential areas and a means for wildlife managers to reduce proximity to people through the manipulation of prey abundance and distribution throughout the landscape.

The composition and characteristics of Cougar prey have been studied extensively in a variety of wildland settings, but diet has not been well studied in wildland-urban landscapes. The Cougar is an adaptive predator that preys on a variety of both small and large animals (Murphy and Ruth 2009). Diets are largely dominated by Deer (Odocoileus spp.; Ackerman and others 1984; Logan and Sweanor 2001; Cooley and others 2008) and Elk (Cervus elaphus; Hornocker 1970; Williams and others 1995; Nowak 1999), but other species may constitute a substantial portion of prey consumed (Sunquist and Sunquist 2002; Murphy and Ruth 2009; Knopff and others 2010). Consistent with other wildland portions of Cougar range, >95% of Cougar diet in Washington is composed of Black-tailed Deer (Odocoileus hemionous columbianus), Mule Deer (Odocoileus hemionus), White-tailed Deer (Odocoileus virginianus), and Elk (Spencer and others 2001; Cooley and others 2008; White 2009). In a wildland-urban landscape in the Santa Ana Mountains of southern California, Cougars killed mostly Mule Deer, but individuals closer to urban centers consumed several Raccoons (Procyon lotor), Opossums (Didelphis virginiana), Coyotes (Canis latrans), and Striped Skunks (Mephitis mephitis; Beier and Barrett 1993). In the wildland-urban environment of the Santa Monica Mountains west of Los Angeles, Mule Deer constituted 95% of prey items and Coyotes comprised 4% (Beier and others 2010). Whether the composition of Cougar diet differs between wildland-urban environments and wildland settings in Washington is not currently known.

Improved understanding of Cougar wildland-urban ecology will require more information on prey use in residential areas beyond southern California. Washington provides one such area, having experienced a 30.4% increase in its human population (US Census Bureau 2008) and extensive landscape alteration since 1990 (Alberti and others 2001; Robinson and others 2005; Hepinstall and others 2008). The western slope of the Cascade Range provides an opportunity to simultaneously investigate predation patterns in both wildland and residential settings.

To better understand Cougar wildland-urban ecology and the potential role of prey in Cougar residential use, we investigated Cougar food habits in wildland and residential portions of western Washington. We quantified and compared prey composition and duration of Cougar presence at predation sites in areas with and without residential development. Black-tailed Deer and Elk are present throughout the study area, so we hypothesized that prey composition would not differ significantly between wildland and residential areas and kill location would not affect duration of time spent at kills. We use our findings to discuss the impacts of residential development on Cougar predation ecology and craft prey-based management strategies aimed at reducing Cougar use of residential portions of the landscape.



Study Area

We examined diet and foraging movements of Cougars in a 3500 [km.sup.2] study area in wildland and residential portions of King and Snohomish Counties, Washington (UTM: Zone 10, 590000 E, 5260000 N, WGS84; Fig. 1). Vegetation, physiographic, and topographic characteristics of the study area have been described at length (Spencer and others 2001; Koehler and Pierce 2003; Kertson and Marzluff 2010; Kertson and others, in press). The climate is moderated by the proximity of a mild, maritime environment and temperatures extremes are rare. Mean annual precipitation ranges from 142 cm in the west to 257 cm in the east and occurs primarily between October 1 and July I (Western Regional Climate Center 2009). Residential development is present throughout the western 1/3 of the study area, largely in densities between 2.5 to 10 residences/ha (suburban) and >10 residences/ ha (urban). Additional suburban and urban development is concentrated in the Interstate 90 corridor extending east through the study area with exurban (>0 to [less than or equal to] 2.5 residences/ha) extending into the Cascade Range foothills. Black-tailed Deer and Elk are the most common ungulates present (Spencer 2002; Bender and others 2004b), but Mountain Goats (Oreamos amercicanus) are present in low numbers at higher elevations (Rice and others 2009). Nonungulate prey present throughout the study area include Beaver (Castor canadensis), Raccoon, Mountain Beaver (Aplodontia rufa), Porcupine (Erethizon dorsatum), Snowshoe Hare (Lepus americanus), Opossum, Ruffed Grouse (Bonasa umbellus), Blue Grouse (Dendragapus obscurus), Turkey (Meleagris gallopavo), Canada Goose (Branta canadensis), and several species of domestic livestock and pets. Other mammalian carnivores present include Bobcat (Lynx rufus), Coyote, Black Bear (Ursus americanus), River Otter (Lutra canadensis), Mink (Mustela vison), and the Long-tailed Weasel (Mustela frenata).

Capture, Collaring, and Monitoring

We attempted to capture Cougars present in the study area each year from November 2003 to December 2008 using trained dogs and large, steel cage traps baited with Cougar-killed or road-killed Deer, Elk, or Beavers (Kertson 2010). Captured individuals were immobilized with a 10:1 mixture of ketamine hydrochloride and xylazine hydrochloride (Plum Creek Pharmaceuticals, Amarillo, TX, USA) administered intramuscularly at a dosage of 8.8 mg/kg ketamine and 0.88 mg/kg xylazine via a 3.0 ml plastic dart fired from a C[O.sub.2] powered dart gun (Dan Inject North America, Fort Collins, CO; Spencer and others 2001). Immobilized Cougars were given a physical examination, ear tagged, and outfitted with a 600 g Global Positioning System (GPS) radio collar (Model GPS Plus-2, Vectronics Aerospace, Berlin, Germany; Model GPS-Telus and GPS-Simplex, Televilt, Lindesberg, Sweden). All Cougar captures and handling were performed in accordance with the University of Washington's Institutional Animal Care and Use Committee under Protocol No. 2185-36.

Global Positioning System radio collars were programmed to take a satellite fix for 180 s every 4 h in an attempt to maximize collar performance and data acquisition (Cain and others 2005; DeCesare and others 2005; D'Eon and Delparte 2005; Lewis and others 2007). Individuals were randomly selected and located weekly using ground-based radio telemetry techniques (Mech 1983) for monitoring and additional data collection (Kertson 2010).

Predation Site Investigation

We employed GPS technology to identify and investigate Cougar predation activity (Knopff and others 2009). We remotely downloaded GPS data sets every 14 to 28 d from Vectronics collars using Uhf bi-directional communication technology and every 28 d with Televilt collars to minimize the time between predation events and investigation in the field. Relocations were plotted in ArcMap 9.3 (Environmental Systems Research Institute, Redlands, CA, USA) and TOPO! 2.6 (National Geographic Holdings, Margate, FL, USA) and examined sequentially to identify potential clusters (White and others 2011). To ensure smaller prey items were accounted for in sampling, we modified the criteria of Anderson and Lindzey (2003) and defined a cluster as [greater than or equal to] 3 relocations [less than or equal to] 100 m apart during a 24-h period. When a cluster was identified, we attempted to investigate as soon as possible to maximize the chance of locating prey remains. We approximated the geometric center of the each cluster on a topographic map and loaded the Universal Transverse Mercator (UTM) coordinates into a handheld GPS receiver to navigate to the site in the field (White and others 2011). We searched for prey remains by walking approximately 5-m concentric circles from the target coordinates and traveling wildlife trails located in the immediate vicinity (within 50 m) of the location until prey remains were located (White and others 2011). Additional predation events were located opportunistically during ground-based radio telemetry sessions and reports of Cougar-human interaction involving marked Cougars. We identified prey remains using hair and skeletal remains (White and others 2011). We assumed all prey remains stemmed from Cougar predation unless evidence of trauma unrelated to Cougar predation was present (such as collision with a motor vehicle, or firearm and archery wounds). Variables collected at potential predation sites included presence-absence of prey remains, portions of carcass found, location of carcass, prey species, prey sex and estimated age (ungulates only), and type of Cougar sign present.

Prey Composition

Accurate information on the average biomass of several prey species in the study area was unavailable, so we used the number of individuals killed. We estimated prey composition as the number of each unique species killed divided by the total number of kills. We pooled our results across Cougar sex and age classes to describe prey use for the population as a whole and to increase our sample size for comparing wildland and residential prey-use patterns. We estimated prey composition for different residential settings in the same way. We report all compositions as percentages, and we pooled all birds and small mammals that were documented in [less than or equal to] 2 predation events into a single "other" category for statistical comparisons.

Duration of Time Spent at Kills

We quantified the duration of time spent at each kill by summing the total number of hours between the first and last observation at the site. We located all Cougar bed sites associated with kills <300 m from the cache site, and subtracted 4 h from the total time spent with the kill for each location observed >300 m from the kill. We did this because Cougars on occasion would temporally leave their kill and return at a later time (sometimes for as little as 4 h, sometimes for days). This methodology allowed us to recognize and quantify when they did, and allowed us to accurately quantify how much time was spent at the actual kill for the analysis. For missed location-fixes, we assumed the cougar was present on the kill if successful location-fixes before and after the missed location-fix were <300 m from the kill site.

Residential Development

Comparison of prey composition in wildland and residential portions of the landscape requires accurate mapping of residential development. We used ArcMap 9.3, the SERGoM vl landcover model (Theobald 2005), 2008 county tax parcel records from King, Snohomish, and Pierce counties, and high-resolution aerial photographs to map wildland and residential landcover within our study area (Kertson 2010; Kertson and others, in press). To supplement these efforts and conduct distance analyses, we used the 2008 tax parcel records, Hawth's Tools (Beyer 2004), and ArcMap Spatial Analyst Tools to model distance to residential development. We used the Select by Attribute tool in ArcMap to identify all tax parcels with a residential structure present (e.g., single family home, multi-family home, or apartment complex) and Generate Polygon Centroid Points in Hawth's Tools (Beyer 2004) to create a point centered in each selected parcel. We used the resulting point layer and the Spatial Analyst Euclidean distance tool to generate a 30 x 30 m grid of distance to residential development. We used the Point Intersect Tool in Hawth's Tools (Beyer 2004) to attach a distance to each kill and Zonal Statistics in ArcMap to summarize the values.

Wildland-Residential Comparison

We classified the setting of each kill based on its location in the broader landscape and distance to residential development. We used a spatial overlay of kill locations and our wildland/residential landcover map with Select by Location in ArcMap to identify and classify wildland and residential kills. However, residential development generates impacts and disturbances that extend beyond the residence (Pickett and others 2001). Within our densely forested study area, noise, light, and other disturbances could be detected up to 500 m from residential development (B Kertson, unpublished data). Consequently, at the wildland-urban interface we classified kills in the wildland portion of the landscape but <500 m from a home as residential. Cougar hearing and sensory perception is likely much more sensitive than a human, so our 500 m delineation likely represents a conservative delineation of the potential spatial extent of disturbances associated with residential development at the wildland-urban interface. We tested for differences ([alpha] = 0.10) between wildland and residential prey compositions using the Chi-square test of homogeneity (Zar 1999).

To determine the potential influence of residential development on the duration of time spent on kills of the same species, we tested for differences ([alpha] = 0.10) using an ANOVA fixed effects model with a two-way interaction term of kill location and species (Oehlert 2000). We tested the hypothesis that Cougars spent less time on Deer, Elk, and Beaver kills near residential development using one-sided t-tests at a significance level of [alpha] = 0.10 (Zar 1999).


We investigated 364 clusters from 15 Cougars (10 males, 5 females), documented 292 kills from these clusters, and located a total of 304 prey remains from a subset (12 males, 8 females) of 32 marked Cougars. Cougars were present on kills for an average of 47.8 h (SD = 36.1, n = 299) and kills were investigated an average of 47 d (SD = 64, n = 302) from their initiation.

Prey Composition

Cougars consumed a wide variety of prey in western Washington, and we documented 17 different wild and domestic species. Cougar diet was dominated by ungulates, with Black-ailed Deer comprising the largest percentage of species killed (Table 1). Beavers comprised 22% of prey items and were the most common nonungulate prey item, followed by Raccoons, Coyotes, and Mountain Beavers (Table 1). Beavers were killed throughout the year, but 61% of kills occurred during late winter and early spring (February-May). A number of novel prey items were documented, including a River Otter (Lontra canadensis) that was killed and consumed by a subadult male <50 m from where he killed a neonate Deer; an adult female that consumed a pair of Black Bear cubs during a single predation event; a subadult male that killed a Canada Goose along the Tolt River; and an adult female that killed a Mallard Duck (Anas platyrynchos) in the Cedar River watershed. Livestock and pets did not constitute a substantial portion of Cougar diet, comprising <3% of all prey items consumed (Table 1) with sheep (Ovis spp., 33%), goats (Capra spp., 28%), and Llamas (Llama glama 17%) constituting the majority of domestic species killed.


Wildland-Residential Comparison

Cougar use of residential areas was highly variable, as individuals spent an average 15.9% of their time (SD = 15.5, n = 19) in residential areas and had a mean of 18.6% home-range area overlap (SD = 17.7, n = 19) with residential areas. We located 244 kills in wildlands and 58 in residential settings. Kills were found an average of 4.16 km (SD = 3.41, n = 300) from residential development, with kills distributed broadly across the landscape (Fig. 2).

Cougar diet was diverse in both wildland and residential portions of the landscape, with many of the same species killed in each setting. Deer were the most common prey item consumed in wildland areas, followed by Beaver, Elk, Raccoon, Mountain Beaver, Coyote, and Opossum. In residential areas, Deer were the most common prey consumed, followed by domestic species, Raccoon, Elk, Beaver, and Coyote (Table 1). Wildland and residential prey compositions were different ([chi square] = 67.30, P < 0.001), with Cougars killing a lower proportion of deer, Beaver, and Mountain Beaver in residential areas and more Coyotes, Raccoons, Opossums, and domestic species (Table 1). Differences between Deer and Beaver predation levels were particularly acute. Predation on these species decreased substantially in areas close to people (wildland = 84.0%; residential = 52.7%) as the proportion of Coyotes and Raccoons killed increased (wildland = 2.7%; residential = 19.0%).

Cougars were present for an average of 48.9 h (SD = 36.5) on wildland kills and 37.7 h (SD = 33.9) on residential kills, with duration of stay in both environments determined by the species killed ([F.sub.15,277] = 3.851, P < 0.00001). The effect of kill location on the duration of stay regardless of species killed was not significant ([F.sub.1,277] = 0.912, P = 0.34), nor was the effect of location significant when comparing kills of the same species ([F.sub.6,277] = 0.317, P = 0.93). Cougars spent an average of 56.9 h (SD = 39.8, n = 144) and 63.2 h (SD = 30.2, n = 21) on Deer and Elk kills in wildland areas compared to 47.5 h (SD = 36.9, n = 24) and 76 h (SD = 46.3, n = 6) in residential settings. Neither Deer nor Elk data supported the hypothesis of decreased duration of stay on kills in residential areas (Deer: t = -1.251, P = 0.11, df = 22; Elk: t = 0.675, P = 0.74, df = 5). Comparison of time spent on Beaver kills did support the hypothesis as Cougars spent less time on Beaver kills in residential areas ([[bar.x].sub.wildland] = 31.6 h, SD = 21.6; [[bar.x].sub.residential] = 22.0 h, SD = 14.9; t = -1.583, P = 0.09, df = 5).


Prey Composition

Investigation of Cougar predation patterns in western Washington revealed a diverse diet. Deer and Elk comprise the largest component of prey items killed in North America (Sunquist and Sunquist 2002; Murphy and Ruth 2009) and prey composition in western Washington provides additional evidence of the importance of an ungulate prey base to maintain a viable Cougar population. While Deer were common throughout the study area and provided a valuable food source in both wildland and residential settings, Cougars frequently exploited non-ungulate prey. Thus, diet in the wildland-urban forests of western Washington appears to be more diverse than previously documented throughout Washington (Spencer and others 2001; Robinson and others 2002; Cooley and others 2008; White 2009), but similar to the diverse diet documented by Knopff and others (2010) using a similar methodology in Alberta, Canada. Consequently, limited documentation of smaller prey items in previous Washington research is due in part to different research objectives, past reliance on VHF radio telemetry methods, and differences in GPS collar performance. Research in northeastern Washington examined predation explicitly within the context of Cougar-ungulate population dynamics and relied all or in part on VHF radio telemetry (Robinson and others 2002; Cooley and others 2008). Spencer and others (2001) relied entirely on VHF radio telemetry to locate kills and their study area did not include wildlands north of Interstate 90 or residential settings where we located a number of nonungulate prey. Fix-location rates of GPS collars employed during the final 2.5 y of our field work routinely exceeded 80%, allowing for documentation of clusters and associated predation events spanning <24 h. Conversely, individual GPS collars employed by White and others (2009) had fix-location rates that rarely exceeded 50 to 60% and fewer clusters spanning <24 h (G Koehler, pers. comm., Washington Department of Fish and Wildlife, Wenatchee, WA).

While it is not unreasonable to assume Cougar diet in other parts of Washington may have a greater preponderance of non-ungulate prey, the consumption of alternative prey, Beavers in particular, is unlikely to match the levels seen in wildland-urban forests of western Washington because of differences in precipitation levels, forest type, and residential development. Frequent precipitation and complex geomorphology (Lasmanis 1991) in the western Cascade Range foothills creates a large amount of high-quality riparian habitat capable of supporting abundant Beaver populations. Beavers in western Washington provide a low risk, high-reward prey item because they are abundant, lack the anti-predatory adaptations and handling times of ungulates, and provide substantial biomass with weights that often exceed 20 kg (B Kertson, unpub, data). Limited handling time and high digestibility increases prey value to a predator (Whelan and Schmidt 2007), and Beavers were consumed in their entirety in <24 h. Predation on Beavers occurred primarily during winter and spring months, possibly decreasing predation on ungulates during a time of year when they may be more vulnerable. Early successional forest and riparian habitat also support persistent Mountain Beaver populations (Arjo and others 2007). Residential development interspersed with suitable Cougar habitat provides an assortment of non-ungulate prey at densities that may exceed those in wildland habitats (Beier and others 2010). Raccoons and Coyotes frequently have higher abundances and concentrate their space use in residential areas that create edge habitats and provide anthropogenic food resources (Riley and others 1998; Fedriani and others 2001).

Use of the cluster investigation methodology allowed for the detection of non-ungulate and smaller prey items, but was not without its limitations. Observed levels of predation on smaller prey, Mountain Beaver, Snowshoe Hare, and Opossum in particular, are likely higher than reported, as these species were abundant throughout the study area and required limited handling time that did not generate clusters. Several clusters were investigated in active Mountain Beaver colonies, but did not yield prey remains. Conversely, our reported proportion of diet consisting of domestic livestock is likely over-estimated, as several hundred wildland clusters unlikely to be domestics were not investigated because of logistical and budget constraints.

Cougar diet and duration at kills may differ significantly between demographic classes and individual Cougars may employ unique foraging strategies (Murphy and Ruth 2009; White 2009; Knopff and others 2010). The preponderance of males and adults in our sample may have biased our results toward these groups. Increasing the sample of subadult and female Cougars would likely increase the number of small and mid-sized prey, as females with offspring and subadults are more likely to kill these species (Murphy and Ruth 2009; Knopff and others 2010), and subadults use residential areas more than adults (Kertson 2010). While we are confident our work adequately captured the diversity of and differences between prey compositions in the wildland-urban environment, future research should focus on the predation patterns of different demographic classes to better understand how these classes influence prey use in wildland and residential portions of the landscape. Findings could be used to generate refined strategies to manipulate prey populations to reduce Cougar use of residential areas.

Wildland-Residential Comparison

Although we found differences in prey composition between Cougars foraging in residential and wildland portions of western Washington, ungulates constituted the bulk of prey items in both settings. Differences likely exemplify disparate prey abundance and vulnerability in wildland and residential settings, coupled with Cougar foraging flexibility and ability to exploit diverse prey resources. Use of alternative prey in residential areas may be common, but ungulates constituted the bulk of prey items in both settings and Cougars do not appear to shift their space-use patterns to take advantage of abundant and vulnerable alternative prey close to people (Kertson 2010). Consequently, predation on non-ungulate prey in residential areas is likely opportunistic and does not constitute a critical component of overall population viability, but may provide valuable short-term subsistence for individual Cougars outside of core, wildland habitats.

Residential development does not appear to significantly reduce the duration of Cougar presence at kills of various species. A lack of differences between wildland and residential kill presence was most likely the result of limited disturbance at residential kill sites. Cougars usually attempt to minimize their exposure to human activity (Van Dyke and others 1986; Sweanor and others 2008; Beier and others 2010; Kertson 2010) and the presence of dense forests and rugged topography at kill sites may have offset their proximity to human activity centers. For Deer and Elk kills, substantial energetic costs are incurred while foraging (Murphy and Ruth 2009), which may select against Cougars that abandon these resources as a result of human-related disturbance. Costs associated with Beaver predation are lower and Cougars may be more likely to abandon these kills following disturbance. However, the small sample size associated with Beaver kills near residential development, and the potentially confounding effect of prey size, limit inferences from this analysis.

Management and Conservation

Ungulate abundance in, and use of, residential habitats has increased with changes in wildland forest management practices and limited hunter access in residential areas (Bender and others 2004a, 2004c). Cougars may not alter space-use patterns to take advantage of abundant small prey near residential centers (Beier and others 2010), but ungulates provide a critical resource to Cougars and some individuals may increase their use of residential settings if these areas provide more abundant and vulnerable Deer or Elk populations (Williams and others 1995; Dickson and Beier 2002; Robinson 2007; Kertson 2010). Successful long-term management and conservation of Cougars in wildland-urban environments may require a reduction in ungulate use of residential environments to ensure these populations do not encourage Cougar presence in habitats close to people. Hunting ungulates in residential areas presents a number of public safety challenges, so a multifaceted approach incorporating adverse conditioning and landscape alterations that reduce habitat quality in residential areas and increase habitat quality in adjacent wildlands may provide the best strategy. However, given the diversity of Cougar diet observed in our wildland-urban study area, managers looking to indirectly reduce Cougar residential use by managing prey may need to incorporate efforts focused on alternative prey. Large-scale removals of these species are likely economically and logistically unfeasible, so local public outreach and education directed at improving animal husbandry practices, storing garbage in secure areas, and not feeding wildlife represent local actions that may help to reduce Cougar residential use.


We thank M White and B Richards for invaluable assistance with Cougar captures. S Kachel, G Spence, E Kitching, K Seidel, S Williams, and A Sengsirtik aided with cluster investigations. The Washington Department of Natural Resources, King County Parks, Seattle Public Utilities, Tacoma Water, Hancock Forest Management, Fruit Growers Supply, and countless private landowners were essential to research success by graciously providing access to their land. Funding and support were provided by the Washington Department of Fish and Wildlife and the University of Washington. We thank A Wirsing, H Cooley, M Wolfe, K Knopff, and 1 anonymous reviewer for comments on earlier drafts that greatly improved the quality of this manuscript. Mention of trade names or suppliers does not constitute endorsement by the federal government.


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Submitted 1 March 2011, accepted 17 June 2011. Corresponding Editor: Clayton Apps.


School of Forest Resources, University of Washington, Seattle, WA 91195;


Washington Department of Fish and Wildlife, 1775 12th Ave NW, Suite 201, Issaquah, WA 98027


US Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA 98195

(1) Current address: Washington Department of Fish and Wildlife, 16018 Mill Creak Blvd, Mill Creek, WA 98012;

(2) deceased
TABLE 1. Prey composition for Cougars (n = 20) in
western Washington (2003-2008) based on 304 kills
(246 wildland, 58 residential) located from Global
Positioning System relocation clusters and VHF
radio telemetry.

                                Kill location

                     Wildland    Residential    Combined
Species                (%)           (%)          (%)

Black-tailed Deer     58.54       41.38          55.26
Elk                    8.54       10.34           8.88
Unknown ungulate       0.81        1.72           0.99
Beaver                24.80       10.34          22.04
Raccoon                2.03       12.07           3.95
Coyote                 0.81        6.90           1.97
Opossum                0.81        1.72           0.99
Mountain Beaver        1.22        0.00           0.99
Domestics              0.00       13.79           2.63
Other                  2.44        1.72           2.30
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Author:Kertson, Brian N.; Spencer, Rocky D.; Grue, Christian E.
Publication:Northwestern Naturalist: A Journal of Vertebrate Biology
Date:Dec 22, 2011
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